output power of 37 dBm, which is a 9-dB BOP. The PAE of over 30% is maintained from a 10.5-dB BOP. Figures 5 and 6 show the measured adjacent channel leakage ratio (ACLR) and PAE characteristics of various conditions for a onecarrier WCDMA signal, respectively. The proposed DPA was optimized with the gate bias adjustment at an average output power of 37 dBm. All ACLR were measured at Ϯ2.5-MHz offset. After the bias optimization (B/O), the proposed DPA shows the significant ACLR and PAE improvement compared with other conditions over a wide output power range. Figure 7 shows the measured power spectrum densities of the proposed DPA before and after B/O. Table 1 shows the measured result summary of various conditions at an average output power of 37 dBm for a one-carrier WCDMA signal. After B/O, the proposed DPA can deliver an ACLR of Ϫ41.2 dBc with a PAE of 37.4% at a 9-dB BOP.
CONCLUSIONSWe have proposed a highly linear and efficient GaN HEMT DPA using unequal drain biases to simply compensate for the soft turn-on characteristic and obtain high efficiency at a large BOP. To verify our method, the proposed DPA is implemented with 25-W GaN HEMTs and tested using a CW and a one-carrier WCDMA signal at 2.6 GHz. Compared with the conventional DPA with the equal drain bias of 28 V, the carrier and peaking cells in the proposed DPA have the drain bias of 23 V and 33 V, respectively. From the measured CW results, the proposed DPA shows higher PAE at 9-dB BOP than the conventional DPA and class-AB PA as well as the maximum output power. For a one-carrier WCDMA signal, the proposed DPA after B/O shows an ACLR of Ϫ41.2 dBc with a PAE of 37.4% at a 9-dB BOP. Therefore, the proposed DPA can be a promising solution for repeater systems to require high linearity and high efficiency at a large BOP.ABSTRACT: Compact dual-band bandpass filter using short stub loaded resonators is presented in this letter, the proposed resonator possesses the advantage that its center frequency of the even mode can be flexibly controlled, whereas that of the odd-mode is fixed. A dual-band filter using pseudo-interdigital SSLR is implemented with three transmission zeros. Meandering SSLR is proposed to obtain independently controlled bandwidth at each band. Two experimental examples of filters have been designed and fabricated, good agreements are shown between the simulation and the measurement. The bandpass filters have very smaller area in comparison of previous works.
Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document.When citing, please reference the published version.
Take down policyWhile the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.